Snowmaking apparatus and methods

Abstract

An improved ducted-fan type snowmaking machine and method wherein an impeller (24) within a duct (22) is driven at a variable speed selected to produce a variable noise level depending on the proximity of the apparatus to an inhabited area. The machine includes air stream straightening vanes (31) for converting a spiraling stream to a linear, laminar flow stream, and a plurality of neucleating nozzles (60) positioned within the confines of the duct. <IMAGE>

We claim: 
     
       1. In snowmaking apparatus having a duct within which is a rotatable impeller for generating an air stream for discharge from the duct, and means for introducing water into the air stream in such quantity as to produce snow, the improvement comprising variable speed drive means for driving said impeller at variable speeds selected to produce predetermined relatively high and low noise levels; and means for varying the amount of water introduced into the air stream commensurately with the variation in the speed of said impeller. 
     
     
       2. The apparatus of claim 1 wherein the speed of said drive means is adjustable to such extent that said relatively high noise level is not less than six times greater than that of said relatively low noise level. 
     
     
       3. The apparatus of claim 2 wherein the percentage reduction between said relatively high and relatively low noise levels is between six and twelve times greater than the corresponding percentage reduction in the speed of said impeller. 
     
     
       4. The apparatus of claim 1 wherein said impeller has blades and said duct has air stream straightening vanes downstream from said impeller blades, said vanes being spaced between about 2 and 5 inches downstream from said blades. 
     
     
       5. The apparatus of claim 4 wherein each of said blades has a tip and a root, said tip having a greater circumferential length than that of said root. 
     
     
       6. The apparatus of claim 1 including nozzle means for introducing nucleating air and water into said air stream, said nozzle means being located within the confines of said duct. 
     
     
       7. The apparatus of claim 1 including nozzle means for introducing nucleating air and water into said air stream, said nozzle means comprising a plurality of nozzles located within the confines of said duct. 
     
     
       8. The apparatus of claim 7 wherein said nozzles are arranged in circular form. 
     
     
       9. In a method of making snow wherein an impeller is rotated in a duct to generate an air stream for discharge from the duct and wherein water is introduced into the air stream in such quantity as to produce snow, the improvement comprising varying the speed of rotation of the impeller to produce relatively higher and relatively lower predetermined noise levels; and varying the amount of water introduced into the air stream commensurately with the variation in speed of rotation of said impeller. 
     
     
       10. The method of claim 9 including varying the speed of rotation of said impeller to such extent as to produce a percentage variation between the relatively higher and lower noise levels of about six times greater than the corresponding percentage variation in the speed of rotation of said impeller. 
     
     
       11. The method of claim 9 including varying the speed of rotation of said impeller to such extent as to produce a percentage variation between the relatively higher and lower noise levels of between six and twelve times greater than the corresponding percentage variation in the speed of rotation of said impeller. 
     
     
       12. The method of claim 9 including introducing a nucleating mixture of water and air into said air stream. 
     
     
       13. The method of claim 12 including introducing the nucleating mixture into said air stream from a position within the confines of said duct. 
     
     
       14. The method of claim 13 wherein the nucleating mixture is sprayed into said air stream via at least one nozzle. 
     
     
       15. The method of claim 13 wherein the nucleating mixture is sprayed into said air stream via a plurality of nozzles. 
     
     
       16. The method of claim 15 including encircling said plurality of nozzles by an annulus.